About one-fifth of the city’s water pipes were installed before 1931, and these aged pipes are responsible for close to half of all water main leaks, the Los Angeles Times reports. The DWP has a $1.3 billion plan to replace 435 miles of deteriorating pipe in the next 10 years, but difficult questions remain about how the agency will find the money, how much it will inconvenience commuters and whether the utility can ever catch up with its aging infrastructure.